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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script type="text/javascript">
      let nums=['hello','worlds']
       nums.map(function(el){
           console.log(el.length);
        })
        // nums.map(el=>console.log(el.length)
        // )

        // var obj={
        //     age:10,
        //     show:()=>{
        //         console.log(this);
        //     }
        // }
        // obj.show();

        // var obj=new Object();
        // obj.1="张三"
        // obj.Name="李四"
        // console.log(obj);
        var map=new Map();
        map.set(1,"张三")
       let a= map.get(1)
       console.log(a)
    </script>
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<body>
    
</body>
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